Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
  • F16F7/121—Vibration-dampers; Shock-absorbers using plastic deformation of members the members having a cellular, e.g. honeycomb, structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
  • B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
  • B60R19/03—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects characterised by material, e.g. composite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R19/00—Wheel guards; Radiator guards, e.g. grilles; Obstruction removers; Fittings damping bouncing force in collisions
  • B60R19/02—Bumpers, i.e. impact receiving or absorbing members for protecting vehicles or fending off blows from other vehicles or objects
  • B60R19/24—Arrangements for mounting bumpers on vehicles
  • B60R19/26—Arrangements for mounting bumpers on vehicles comprising yieldable mounting means
  • B60R19/34—Arrangements for mounting bumpers on vehicles comprising yieldable mounting means destroyed upon impact, e.g. one-shot type
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D21/00—Understructures, i.e. chassis frame on which a vehicle body may be mounted
  • B62D21/15—Understructures, i.e. chassis frame on which a vehicle body may be mounted having impact absorbing means, e.g. a frame designed to permanently or temporarily change shape or dimension upon impact with another body
  • B62D21/152—Front or rear frames
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D25/00—Superstructure or monocoque structure sub-units; Parts or details thereof not otherwise provided for
  • B62D25/08—Front or rear portions
  • B62D25/082—Engine compartments
  • B62D25/085—Front-end modules
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D29/00—Superstructures, understructures, or sub-units thereof, characterised by the material thereof
  • B62D29/001—Superstructures, understructures, or sub-units thereof, characterised by the material thereof characterised by combining metal and synthetic material
  • B62D29/005—Superstructures, understructures, or sub-units thereof, characterised by the material thereof characterised by combining metal and synthetic material preformed metal and synthetic material elements being joined together, e.g. by adhesives
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/003—One-shot shock absorbers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F7/00—Vibration-dampers; Shock-absorbers
  • F16F7/12—Vibration-dampers; Shock-absorbers using plastic deformation of members
  • F16F7/124—Vibration-dampers; Shock-absorbers using plastic deformation of members characterised by their special construction from fibre-reinforced plastics

Definitions

• Energy absorbing device with fibers embedded in a plastic material, and associated front face
• the present invention generally relates to energy absorbing devices for a motor vehicle.
• energy absorption devices are known for Danner-type medium-intensity shocks. These energy absorbers are typically interposed between the front of the vehicle and the main beams, or between the front face and the lower longitudinal members of the vehicle. Lower spars are also known as "cradle extensions".
• shock absorbers are typically formed of tared metal boxes to plastically deform in the event of shocks of intensity greater than a predetermined energy, absorbing a portion of the impact energy.
• Such absorbers are described for example in FR 0756932.
• the force causing the plastic deformation of the energy absorber also called energy absorber calibration, must be as high as possible to allow effective dissipation of the energy absorber. energy in a small footprint. It must be greater than a lower limit Fmini.
• This force must also be lower than the calibration of the main beams or lower longitudinal members, so as not to cause permanent deformation of the side members in case of shocks.
• the calibration must be lower than an upper limit Fmax.
• the tare of the energy absorber device is very close to Fmaxi by a lower value.
• the difference between Fmini and Fmaxi is about 20%, the energy absorbing device to be in this range.
• Box-type shock absorbers generally have good temperature stability. On the other hand, they have a high mass and are of complex structure, since they generally comprise several pieces assembled to each other: a support base, a block of aluminum foam or a metal box, a deformable envelope to the The interior of which is inserted the block of metal foam or the metal box etc.
• these absorbers are expensive, because their assembly requires a lot of time and involves a large number of parts.
• the invention aims to provide a shock absorber device that is simpler, less expensive, but whose performance is stable with temperature.
• the invention according to a first aspect relates to an energy absorption device comprising a structure designed to plastically deform under the effect of a given energy shock by absorbing a part of the impact energy, the structure being of a material comprising:
• High tenacity fibers embedded in the matrix the majority of the fibers having a length of between 0.1 and 10 mm, the material comprising between 2 and 10% of high tenacity fibers by weight.
• the device may also have one or more of the following features considered individually or in any technically feasible combination:
• the material comprises between 5 and 9% by weight of high-tenacity fibers
• the high-tenacity fibers are glass, carbon or aramid fibers
• the matrix is a styrenic polymer, or a polycarbonate, or a polyamide, or a saturated polyester, or a polyolefin, or an elastomer, or an alloy of one or more of said material;
• the majority of the fibers have a length of between 0.1 and 7 mm;
• the structure is a honeycomb structure, comprising a plurality of walls together defining hollow cells juxtaposed to each other.
• the invention relates to a front face of a motor vehicle, the front face comprising a rigid cross member having side portions disposed in the longitudinal extension of the longitudinal members of the vehicle, and at least one energy absorbing device having the above features, interposed longitudinally between one of the longitudinal members and one of the side portions of the cross member.
• the invention relates to a front face of a motor vehicle, the front face comprising a rigid frame comprising:
• the front panel may also have one or more of the following features considered individually or in any technically feasible combination:
• the upper and lower crosspieces are made of a first material comprising a matrix made of a first plastic material, the legs being made of a second material different from the first material and comprising a matrix consisting of the first plastic material;
• the upper and lower rails are a first material comprising a matrix of a first plastic material and an elastomer, or a shock copolymer;
• the upper and lower crosspieces are made of a first material comprising a matrix made of a first plastic material, the legs being made of a second material different from the first material and comprising a matrix consisting of a second plastic material different from the first, the first and second material comprising a chemical coupling additive of the first and second plastics, provided to strengthen the connection of the legs with the upper and lower crosspieces.
• FIG. 1 is a front view of a rigid frame comprising a plurality of energy absorbing devices according to the invention, the rigid frame being adapted to be integrated in a front face of a motor vehicle;
• FIG. 2 is a graph showing the resistance force of each of the energy absorption devices of the frame of FIG. 1, as a function of the depression, at different ambient temperatures;
• FIG. 3 is a graph showing the evolution of the taring of a polypropylene copolymer energy absorber device not according to the invention as a function of the temperature;
• FIG. 4 is a graph similar to that of FIG. 2 for a polypropylene shock absorber device not according to the invention.
• FIG. 5 shows energy absorption devices and certain elements of a front face according to a second embodiment of the invention.
• the longitudinal and transverse directions, front and rear are heard relative to the direction of normal movement of the vehicle.
• the frame 1 shown in Figure 1 is intended to be substantially vertically integrated in a front face of a motor vehicle. It comprises an upper cross member 3, a lower cross member 5, and two legs 7, provided to be arranged substantially vertically. Each leg 7 connects one end of the upper transverse beam 3 to the corresponding end of the lower crossbar 5.
• the sleepers and jambs delimit between them a central opening 9.
• the zones 1 1 of the frame 1, located at the intersection of the upper rail 3 and legs 7, are intended to be placed substantially in the longitudinal extension of the main longitudinal members of the motor vehicle.
• the zones 13 located substantially at the intersection of the lower cross member 5 and jambs 7, are intended to be placed in the longitudinal extension of the lower longitudinal members of the motor vehicle.
• each of the zones 1 1 and 13 constitutes an energy absorption device calibrated for medium intensity shocks (Danner shocks).
• the zones 1 1 and 13 of the frame are made of a material comprising:
• high tenacity fibers embedded in the matrix the majority of the fibers having a length of between 0.2 and 10 mm, the material comprising between 2 and 10% of high tenacity fibers by weight.
• matrix is meant here the chemical or copolymer component constituting the bulk of the material.
• the other components are additives that are dispersed and embedded in the matrix. These additives may be large, such as the fibers mentioned above.
• the additives can also be dispersed and intimately mixed chemical components in the form of very fine nodules or particles in the matrix.
• the matrix mainly comprises a polyolefin, or a polyamide, or a styrenic polymer, or a polycarbonate, or a saturated polyester, or an elastomer.
• the matrix consists of a polyolefin, or a styrenic polymer, or a polycarbonate, or a polyamide or a saturated polyester or an elastomer.
• the polyolefin is typically a polypropylene or a propylene-ethene copolymer, or a propylene-hexene copolymer, or a propylene-octene copolymer, or an ethylene-octene copolymer, or a propylene-ethylene-butene terpolymer.
• High tenacity fibers are typically glass fibers, carbon fibers, or aramid fibers.
• the fibers are of the type known as “short fibers” or "long fibers". Short fibers typically have a length of less than 1 mm. The long fibers, for most of the fibers, have a length of between 1 and 7 mm.
• most of the fibers have a length of between 0.5 and 5 mm. It should be noted that the length to which reference is made here corresponds to the length of the fibers constituting the finished product. Part of the fibers break during the plasticization and injection of the material in a mold, at high temperature.
• the material comprises, as indicated above, between 2 and 10% of fibers by weight, the remainder consisting of the plastic matrix, and possibly other additives. More preferably, the material comprises between 5 and 9% by weight of fibers.
• the zones 1 1 and 13 are typically each a cellular structure, comprising a plurality of hollow cells 15 juxtaposed to each other.
• the cells 15 are defined by walls 17, which may be common to several cells where appropriate.
• the walls consist of the material described above.
• the cells 15 are for example closed towards the front of the vehicle by a front wall 18, and open towards the rear of the vehicle. They are typically closed up, down, to the right and to the left of the vehicle.
• the front wall 18 has an orifice 19, to allow the escape of air when the energy absorbing device is crushed.
• the cells 15, considered in sections perpendicular to the longitudinal direction, can have all kinds of shapes. In the example of Figure 1, they are substantially square or rectangular. They can also be hexagonal, triangular, circular, oval, etc.
• FIG. 2 is a graph which shows the evolution of the resistance force to the depression (in ordinate, expressed in kilo Newton kN), as a function of the deformation of the material under the effect of the displacement of the impacting object ( on the abscissa, expressed in millimeters), for each of the zones 1 1 and 13.
• FIG. 2 comprises several curves, each curve corresponding to the behavior of the zones 1 1 or 13 at a different ambient temperature. These curves were made for absorption devices of energy with a copolymer propylene-ethylene matrix, filled with 7.5% long glass fibers.
• all the curves comprise a first section slightly inclined between 0 and 50 mm, followed by a steeply inclined front 21, close to the vertical.
• the slightly inclined section corresponds to a moment when the object that impacts the front face has not yet reached the rigid structures of the front face.
• the resistance force increases abruptly, which corresponds to the front 21.
• the height of the front 21 corresponds to the calibration of the energy absorber device.
• the setting remains between 1 50 kN and 170 kN. No peak greater than about 170 kN is observed, so that the vehicle body, in particular the upper and lower spars, are perfectly protected. These high values also allow efficient energy absorption. Between 50 and 80 ° C, the absorber becomes a little more flexible, while maintaining a setting greater than 100 kN. The body structure is always perfectly protected, and the energy is sufficiently absorbed.
• shock absorption devices described above exhibit a remarkably homogeneous behavior with respect to the ambient temperature.
• the addition of reduced amounts of fiber induces a particular behavior of the shock absorbing device.
• the matrix breaks very gradually, in a fragile mode.
• the material undergoes a very gradual decohesion, from the front to the rear of the vehicle, without sudden rupture of the absorber.
• Such deformation mode allows a very efficient dissipation of energy, and provides a stable temperature setting, just below the nominal rating of the beams. At high temperature, the setting decreases slightly, but in proportions lower than those of the polymer material constituting the matrix.
• an energy absorber having the same structure as that of the areas 1 1 and 13 of Figure 1, calibrated to provide a resistance of about 150 kN at room temperature, offers resistance to crushing which varies significantly depending on the temperature.
• the curve of Figure 3 has been established for a polypropylene absorber. The setting decreases regularly with the temperature. At 80 ° C, this setting is only 70 kN, which is insufficient to absorb the energy resulting from a shock. The object impacting the front panel may then collide with the body structure and cause it damage. irreversible. On the contrary, at -20, the energy absorbing device is much too rigid (calibration of about 280 kN). The setting of the energy absorbing device becomes greater than the calibration of the side members, such that these side members will deform before the energy absorbers.
• the mode of deformation of the energy absorbing devices of the invention is different from that of the energy absorber devices of unfilled ductile polymer.
• the latter are deformed by buckling, and more specifically by bundling.
• the structure forms folds, in the manner of a plastic bottle that is crushed.
• shock absorbing devices made of a material comprising a ductile plastic matrix and a high concentration of high-tenacity fibers, for example more than 15% of high-tenacity fibers, do not offer any behavior. satisfactory.
• the material is extremely brittle at low and medium temperatures, especially between -30 and +20. The material is then no longer able to dissipate the energy effectively: it collapses brutally and divides into multiple pieces.
• the lower and upper sleepers may advantageously be made of a material different from that of the legs. Indeed, the specifications of sleepers is different from that of energy absorption devices.
• the upper and lower sleepers are designed to absorb energy throughout the speed range of the vehicle and to resist intrusion by maintaining the integrity of the structure.
• the lower and upper sleepers are made of a material comprising a matrix identical to that of the legs 7, and an elastomer, for example EPDM.
• the frame can advantageously come from material. It is for example obtained by bi-injection or co-injection of jambs and sleepers in the same mold.
• bi-injection is meant an injection made in a mold having different injection orifices, each dedicated to one of the materials to be injected.
• co-injection is meant an injection in a mold comprising a single injection orifice, the two materials being successively injected into the mold.
• the upper and lower crosspieces may be made of a first material comprising a matrix made of a first plastic material, the legs being in a second material different from the first material, and comprising a matrix consisting of a second material. different plastic from the first plastic material.
• the first and second materials each comprise a chemical coupling additive of the first and second plastics, intended to strengthen the connection of the legs with the upper and lower rails.
• the first plastic may be polyamide, and the second plastic polypropylene, or vice versa. Additives are known for chemically coupling these plastics.
• the frame obtained came from injection. This makes it easy to integrate in the context of functional areas such as under-projector supports, a technical front face, structural carrier zones of shield skin or accessories such as fog lamps, calenders, shutters controlled etc. ..
• the energy absorbing devices 31 are not integrated in a frame of the front face.
• the front face comprises for example in this case a cross member 33, for example metal, the energy absorbing devices 31 being interposed between two side portions 35 of the crosspiece 33, and the longitudinal members 37 of the vehicle.
• Each of the energy absorbing devices 31 is a honeycomb structure of the type described above, consisting of a material with a ductile plastic matrix, and high tenacity fibers.
• each device has four rows of three cells.
• the front face may in particular comprise plates, not shown in Figure 5 fixed by a first large face each to a spar 37, the energy absorbing device being rigidly fixed to a second large face of said platen.
• the longitudinal members 37 may be the main longitudinal members of the vehicle. They can also be the lower longitudinal members of the vehicle.
• the energy absorption devices described above, and the front panels incorporating such energy absorbing devices, have multiple advantages.
• the energy absorbing devices have a reduced mass, because they are made entirely of a filled plastic material. They are simple in design, and include only a reduced number of pieces (one piece per energy absorbing device). They can be obtained easily, for example by injection.
• the front faces incorporating these energy absorption devices especially when they comprise a frame of the type described with reference to FIG. simple manufacturing and assembly. In particular, it is possible to integrate multiple functional areas on such frames.
• the energy absorption devices have a remarkably stable temperature setting.
• the energy absorbing devices have been described above for the absorption of medium intensity shocks. However, it could be calibrated to absorb the energy of shocks of lower or higher intensity.
• These energy absorbing devices can be used not only in a front face of a motor vehicle, but also in the rear or in any other area of a vehicle where it is necessary to absorb a calibrated energy.
• the legs 7 may be integrally formed in the material adapted for the zones forming energy absorption devices 1 1 and 13.
• the legs 7 may comprise zones made up of the material adapted to them. zones 1 1 and 13, and other zones made of another material, for example material constituting the crosspieces 3 and 5.
• the energy absorbing devices of the invention have been described in relation to FIG. 1 as constituting zones of a frame with two crosspieces and two jambs. These devices could be frame areas having all kinds of shapes, having only one cross, or more than two sleepers, or having any other shape.
• the energy absorbing devices have been described in relation to FIG. 5 as integrated blocks between a metal cross member and the longitudinal members of the vehicle. These blocks could be integrated into front faces made differently.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Architecture (AREA)
• Structural Engineering (AREA)
• Vibration Dampers (AREA)
• Body Structure For Vehicles (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=45420681

Family Applications (1)

Country Status (11)

Families Citing this family (6)

Citations (8)

Family Cites Families (20)

• 2010
  • 2010-11-22 FR FR1059581A patent/FR2967740B1/fr not_active Expired - Fee Related
• 2011
  • 2011-11-21 ES ES11802486.8T patent/ES2517442T3/es active Active
  • 2011-11-21 US US13/988,934 patent/US9051984B2/en not_active Expired - Fee Related
  • 2011-11-21 CA CA2818282A patent/CA2818282A1/fr not_active Abandoned
  • 2011-11-21 JP JP2013540422A patent/JP2014505838A/ja active Pending
  • 2011-11-21 WO PCT/FR2011/052711 patent/WO2012069746A1/fr not_active Ceased
  • 2011-11-21 KR KR1020137015734A patent/KR20130140086A/ko not_active Ceased
  • 2011-11-21 BR BR112013012373A patent/BR112013012373A2/pt not_active IP Right Cessation
  • 2011-11-21 MX MX2013005765A patent/MX2013005765A/es unknown
  • 2011-11-21 EP EP11802486.8A patent/EP2643192B1/fr not_active Not-in-force
  • 2011-11-21 CN CN201180065595.3A patent/CN103328274B/zh not_active Expired - Fee Related

Patent Citations (8)

Also Published As

Similar Documents

Legal Events